Knitted mesh cushion or pad for laboratory clamps and method of making



May 8, 1962 A. H. COHEN ETAL KNITTED MESH CUSHION 0R PAD FOR LABORATORYCLAMPS AND METHOD 0F MAKING Flled June 26, 1959 T TGR NE YS UnitedStates Patent Otlice 3,3Z,849 Patented May 8, 1962 3 032 849 KNITTEDMESH CUSI-IO OR PAD FOR LABORA- TRY CLAMPS AND METHOD F MAKHNG AlbertHoward Cohen, Newark, and Alfred Minor Goodloe, Westfield, NJ.,assignors to Metal Textile Corporation, Roselle, NJ., a corporation ofDelaware Filed June 26, 1959, Ser. No. 823,169 12 Claims. (Cl. 24-262)This invention relates to padding for holding test tubes or otherdevices in clamps, particularly where the test tube or other device must'be heated.

lt is conventional practice to provide some sort of padding on clampswhich are used to grip test tubes and similar articles which are to beheated over a llame. It has been a serious disadvantage that the paddingused for the clamps is damaged by the heat, or becomes hardened so thatit no longer serves its intended purpose.

It is an object of this invention to provide an all-metal, resilient,knitted-mesh cushion or pad for laboratory use for clamping test tubes,glassware and other fittings. The pad provides a more uniform pressureagainst the test tubes, glassware or other items and prevents thebreaking of the glassware when clamped tightly enough to support theweight. It also provides enough resilience to permita certain amount ofadjustment, where required, without risk of breaking the glass item.

Prior practice has been to use rubber cushions and asbestos cushions.Molded rubber cushions are limited to ya maximum temperature of around150 C.; and they are laffected by the organic solvents commonly used inlaboratories. The rubber cushions become brittle with age `and becomeimmediately useless when exposed to excessive temperatures. Sometimesthe rubber cushions fuse to the apparatus with which they are being usedand this requires involved cleaning operations or the discarding oftheapparatus.

Asbestos cushions withstand higher heat but have the disadvantage thatthey lack sufficient resiliency to properly cushion between the metalparts of a clamp and the glass item held in the clamp. The asbestoscushions char when exposed to a arne and they `ca'lcine and becomepowdery. Cotton used to hold the asbestos fibres in place deteriorateswith high temperature.

Asbestos cushions have had the additional objection that they aredifficult to clean; they require long periods to dry; and because oftheir capillary nature, often soak up substances which harden in thecushion and destroy the resiliency.

The knitted metal cushion of this invention overcomes the oibjec'tionsencountered with molded rubber andasbestos cushions and it obtains onevery important, and

unexpected, result in that it holds apparatus securely over a wide rangeof tightening pressures which allows valignment and adjustment of thepieces of the apparatus without the necessity of changing the clampscrew fitting. In other words, the knitted mesh cushion does not releaseits pressure suddenly, as is so'often observed in other cushions.

One of the advantagesof the knitted mesh cushion of this kinvention isthat it retains its resiliency for an indenite'period, in spite ofexposure vto direct heat. The cushion of this invention can be Vcleanedveasily and immediately-replaced ina clamp.V `Even Yifencrusted matteris deposited within the knitted mesh, it can be easily broken up andwashed out. The cushion can be made of wire constructed of metals -oralloys to withstand corrosion and temperature-conditions which will beencountered in uses for which the cushion is intended.

Other objects, features and advantages of the invention will appear orbe pointed out as the description proceeds.

ln the drawing, forming a part hereof, in which like referencecharacters indicate corresponding parts in all the views;

FIGURE 1 is atop plan view, partly in section, showing `a clamp equippedwith a knitted mesh cushion in accordance with this invention;

FIGURE 2 is a fragmentary side view of the clamp shown in FGURE l;

FlGURE 3 is a diagrammatic view illustrating one of the steps in themanufacture of the knitted mesh cushion of this invention;

FIGURES 4-8 are diagrammatic views showing other steps in themanufacture of the knitted mesh cushion of this invention; and

FIGURE 9 is a perspective View of the cushion produced by the stepsillustrated in FIGURES 3-8 ofthe drawing.

The clamp shown in FIGURE l includes two levers 11 and 12 connectedtogether by a pivot 14. One of the levers has an extension 16 whichserves as a bracket for attaching the clamp to a support.

The levers 11 and 12 are preferably of channel cross section throughouta portion of their length, with the channels confronting one another;and there yis a spring 18 wrapped around the pivot 14 and Ibearingagainst the Walls of the levers 11 and 12 to urge the levers away fromone another.

A bolt 26 extends through the levers 11 and 12. This bolt has a head 21which bears against the lever v12; and there is a wing nut 22, threadedon the yboltV 20, and in contact with the lever 11. The ends of thelevers 11 and 12 remote from the pivot 14 are flattened and curved toform jaws 24 of the clamp. Rotation of the nut 22 in one direction movesthe clamp jaws 24 together; and rotation of the nut in the otherdirection permits the spring 1S to move the jaws 24 away from oneanother.

There are knitted mesh cushions '26 'on each of the clamping jaws 24.These cushions 26 are flattened sleeves into which the jaws 24 fit. Thecushions 26 will bend dong their length to the necessary contour to tthe curved :shape ofthe jaws 24. Clamp jaws of the type f illustratedare curved but are not arcs of a circle throughout their length. Thecushion 26 is made to litV snugly on the clamp jaw so that frictionassists in holding the cushion in'place. However, the knitted mesh ofthe cushion bends easily enough so that the cushion can be 'removed fromthe -clamp jaw whenever znecessary vfor cleaning.

In the manufacture of the knitted `mesh cushions of this invention, thewire is originally knitted to form a tube 23 (FIGURE 3) which is thenVflattened by passing between rollers V29, or in any other suitable stepfor flattening the tulbe under pressure light enough to leave theknitted mesh loose and resilient.

To add still further to thel resilience ofthe cushion 'of .thisinvention, the flattened tube of FIGURE 3 is'corrugated by giving it ashallowangle crimpto form cor- 3 rugations 30 (FIGURE 4) extendingtransversely of the length of the flattened tube.

The size of the wire used to make the knitted mesh tube 28, and thematerial used for the wire, depend upon the working conditions for whichthe cushion is intended. Various degrees of resilience can be obtainedby different choices in the size of the wire. Larger wires provide lessresilience, but may be desirable on larger cushions. The material usedshould be corrosion-resistant for the working conditions to beencountered. Stainless steel wire is particularly suitable.

For the manufacture of a cushion, a desired length is cut from the tube28 and this length of knitted mesh is indicated in FIGURE 5, andsubsequent figures, by the reference character 2S. This corrugated meshmaterial is then folded back on itself at 30, as shown in FIGURE 5. Withthe corrugations at a preferred angle of 45 to the length of theflattened tube, this folding back puts the upper corrugations 30 atright angles to those in the bottom length of the fold and the resultingcriss crossing of the corrugations increases the bulk of the foldedmaterial.

FIGURE 4a is a top plan view showing the corrugations 30 extendingtransversely across the mesh 28. At the right-hand end of FIGURE 4a thematerial is shown folded back on itself and the criss cross relation ofthe corrugations of successive layers is clearly shown.

The cut ends of the mesh 28 are preferably spot welded together at thelocation 32.

The further steps in making the cushion are illustrated in FIGURES 6-8,but because of the scale of the drawing, no attempt is made to show thecorrugations or the double thickness obtained by flattening the tube.The flattened tube is considered one layer.

A thin steel strip or form 36 is placed on the knitted mesh 28 near oneend and the portion of the mesh beyond the form 36 is bent up over theform as shown in FIGURE 6. The form 36 is then rotated about itsright-hand edge in FIGURE 6 to swing the left-hand end of the mesh 2Sthrough an arc indicated by the dotted line 38. This folds a portion ofthe knitted mesh 28. The form 36 is again rotated about the edge whichhas now become the right-hand edge and in this manner the knitted mesh28 is folded successively until the entire length of the mesh has beenrolled around the form 36, as indicated in FIGURE 7.

The form 36 is then withdrawn and an electrode strap 40 is inserted intothe cushion 26. This electrode strap 40, however, is not inserted in thesame location as that occupied by the form 36. In order to have as muchresilience as possible at the front of the cushion, the electrode strap40 is inserted under the third layer of knitted mesh, this being theminimum number of layers that is used for the back of the cushion.

After insertion of the electrode strap 40, the knitted mesh material issecured by spot welds 42. These spot welds attach an end fold of themesh material (there being two layers in the end fold as a result of thefolding back of the flattened tube as shown in FIGURE to the next layerbelow, that is, the third layer. These spot welds keep the knitted meshmaterial from unrolling and thus complete the forming of the cushion 26.The electrode strap 40 is preferably copper, to facilitate the spotwelding without danger of having the electrode weld to the knitted mesh.The spot welding is preferably a resistance weld.

The electrode strap 40 is removed from the cushion after the spotwelding operation, leaving the final cushion as shown in FIGURE 9. Theopening left by the removal of the electrode strap 40 provides theopening for insertion of the clamp jaws with which the cushion is to beused.

The preferred embodiment of the invention has been illustrated anddescribed, but changes and modification can be made and some featurescan be used in different combinations without departing from theinvention as defined in the claims.

What is claimed is:

l. Apparatus for holding a test tube or the like including two clampjaws having confronting faces that diverge from one another towardmid-regions of the length of the faces, a cushion on each of theclamping jaws, each of the cushions comprising a plurality of layers ofwire mesh having stitches knit together and with the layers comprisingconvolutions of a spiral, each of which convolutions is in contact witha next adjacent convolution, the axis of the spiral extending in thedirection of the length of the faces, each of the jaws extending throughits associated cushion between two convolutions of the spiral, theconvolutions of each cushion being curved both circumferentially andaxially along their length to t the diverging contour of the face of theclamp jaw, and means for holding the jaws and cushions clamped to a testtube or the like.

2. The apparatus described in claim l and in which each of the clampingjaws extends between convolutions of the spiral of its cushion rearwardof the axis of the spiral whereby most of the resilience of the cushionis in front of the clamp jaw, and the means for holding the jaws is ascrew that is adjustable to change gradually the pressure of the cushionagainst the test tube or the like.

3. The apparatus described in claim l and in which the knitted wire meshmaterial is formed with a corrugated contour having the corrugationsextending at an angle to the direction of the length of the axis of thespiral, and the corrugations of successive layers are at complementaryangles so that the high part of one corrugation contacts with thesurface of the next layer of material at low points of its corrugationsto increase the resilience of the cushion and to increase the extent ofthe cushion outwardly from the face of the clamp jaw.

4. The apparatus described in claim l and in which at least twoconvolutions of the spiral are behind the clamp jaw and there arefastening means holding said two convolutions together to preventunwinding of the spiral.

5. The apparatus described in claim 3 and in which the corrugations ofone layer are at right angles to the corrugations of the next layer.

6. The apparatus described in claim l and in which the jaws are curvedand the curves change in their radius of curvature along the length ofthe jaws whereby the cushion cannot come olf the end of either jawwithout having the cushion bend to a different contour during themovement necessary to remove cushions from the clamp jaw.

7. A slip-over cushion for telescoping over a clamping jaw that holds atest tube or the like, said cushion comprising a flattened roll havinglayers of wire mesh with loops of the wire knit together, and havingcertain layers of the roll open at one end of the roll spaced from oneanother across a clearance that is for receiving a clamping jaw insertedendwise into the roll.

8. The cushion described in claim 7 and in which the cushion is aspirally wound roll of the knitted wire mesh and the layers are formedof flattened tubular material so that certain of the layers have theirends of one piece vconstruction with the ends of the next successivelayer of the spiral.

9. The cushion described in claim 7 and in which the clearance forreceiving the clamp jaw is offset from the .center of the roll so thatthe cushion has most of its layers and resulting resilience on one sideof said clearance.

10. The cushion described in claim 7 and in which the cushion is made upof convolutions that are twolayers thick and with the sides of bothlayers of each convolution of one piece construction.

11. The slip-over cushion described in claim 7,and in which the layersof knitted wire mesh are corrugated `for greater resilience.

12. The slip-over cushion described in claim 11, and in which thecorrugations extend transversely of the length of the knitted wire meshmaterial, and successive layers of the material have corrugationsextending crosswise of each other for greater resilience of the cushion.

References Cited in the file of this patent UNITED STATES PATENTS FisherJan. 24, 1933 Crary June 5, 1934 Schmidt Nov. 17, 1936 Dyer Sept. 14,1937 Goodloe et al. Feb. 17, 1942 Hefter Dec. 19, 1944 Matthews Oct. 12,1954

